Being a pop idol isn't always fun.

Lead singer Hyorin of chart-topping K-pop girl group SISTAR was forced to apologize on Twitter this week, after footage of her not appearing to be enjoying herself at a recent autograph signing for fans of the group, caused an online backlash, according to the website allkpop.

"Hello, this is Hyorin. I'm so sorry because I think I unintentionally disappointed you guys at the fan signing," the singer wrote.

"The event where I was actually with the fans was a fun time for me. However, I think my candid actions with the fans was enough to cause a misunderstanding. From now on, I will not disappoint you guys. I'm sorry. I will be Hyorin who tries her best."

A representative from the group's record label Starship Entertainment claims the photograph doesn't tell the whole story.

"The overall mood of the fan signing was good," the rep explained.

"We think there was a misunderstanding from the short clip. Hyorin normally greets her fans candidly. The fans weren't offended since it was a fan-meeting situation. We hope there aren't any misunderstandings."

The controversy first arose when an amateur video shot by a fan showed the singer apogizing for lookin so blase, according to eNEWS,
"I'm not in a bad mood, so don't misunderstand," Hyolyn said.

"Don't worry about our expressions, since a person can't be smiling all 365 days, right? There are times when a person might not have an expression. I'm not in a bad mood. I just don't have a expression today."

K-pop fan Teikitekahioho sees Hyorin's behavior as part of a pattern.

"I feel sorry for her, but lately I found her less enthusiastic," Teikitekahioho wrote in response to the allkpop article. "It's been a while since I heard her laughing."

But SISTAR fan lili3456 feels everyone should give the star a break.

"I actually feel sorry for her," she wrote.

"Yes, maybe she was rude, but how many of us have had a bad day and took it out on others? She was probably tired as hell, felling bad and had to work for many hours more. I would be a mess too. She did something wrong and apologized. Good for her for not making excuses for her behavior but taking responsibility for that."

Perhaps Hyorin missed a meal, although not reportedly a common occurrence for her band.

Earlier this month, over a late lunch at a Korean restaurant, the members of SISTAR opened up to the Mnet program "M! Countdown" about how they avoid starving themselves to stay thin.

"To show a healthy image, we just have to eat," Dasom said.

"We can't sing without food. We do get something called 'camera massage,' so we don't gain as much weight as we used to."

"We don't gain weight, but we don't lose either," Soyoo quipped.